simple_list.h File Reference

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Detailed Description

Simple macros for type-safe, intrusive lists.

Intended to work with a list sentinal which is created as an empty list. Insert & delete are O(1).

Author:

(C) 1997, Keith Whitwell

Data Structures
struct	simple_node
Defines
#define	remove_from_list(elem)
	Remove an element from list.
#define	insert_at_head(list, elem)
	Insert an element to the list head.
#define	insert_at_tail(list, elem)
	Insert an element to the list tail.
#define	move_to_head(list, elem)
	Move an element to the list head.
#define	move_to_tail(list, elem)
	Move an element to the list tail.
#define	make_empty_list(sentinal)
	Make a empty list empty.
#define	first_elem(list)   ((list)->next)
	Get list first element.
#define	last_elem(list)   ((list)->prev)
	Get list last element.
#define	next_elem(elem)   ((elem)->next)
	Get next element.
#define	prev_elem(elem)   ((elem)->prev)
	Get previous element.
#define	at_end(list, elem)   ((elem) == (list))
	Test whether element is at end of the list.
#define	is_empty_list(list)   ((list)->next == (list))
	Test if a list is empty.
#define	foreach(ptr, list)   for( ptr=(list)->next ; ptr!=list ; ptr=(ptr)->next )
	Walk through the elements of a list.
#define	foreach_s(ptr, t, list)   for(ptr=(list)->next,t=(ptr)->next; list != ptr; ptr=t, t=(t)->next)
	Walk through the elements of a list.

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Define Documentation

#define at_end	(	list,
		elem		)	((elem) == (list))

Test whether element is at end of the list.

Parameters:

	list	list.
	elem	element.

Returns:

non-zero if element is at end of list, or zero otherwise.

#define first_elem

(

list

)

((list)->next)

Get list first element.

Parameters:

list

list.

Returns:

pointer to first element.

#define foreach	(	ptr,
		list		)	for( ptr=(list)->next ; ptr!=list ; ptr=(ptr)->next )

Walk through the elements of a list.

Parameters:

	ptr	pointer to the current element.
	list	list.

Note:

It should be followed by a { } block or a single statement, as in a for loop.

#define foreach_s	(	ptr,
		t,
		list		)	for(ptr=(list)->next,t=(ptr)->next; list != ptr; ptr=t, t=(t)->next)

Walk through the elements of a list.

Same as foreach but lets you unlink the current value during a list traversal. Useful for freeing a list, element by element.

Parameters:

	ptr	pointer to the current element.
	t	temporary pointer.
	list	list.

Note:

It should be followed by a { } block or a single statement, as in a for loop.

#define insert_at_head	(	list,
		elem		)

Value:

do {                                            \
   (elem)->prev = list;                         \
   (elem)->next = (list)->next;                 \
   (list)->next->prev = elem;                   \
   (list)->next = elem;                         \
} while(0)

Insert an element to the list head.

Parameters:

	list	list.
	elem	element to insert.

#define insert_at_tail	(	list,
		elem		)

Value:

do {                                            \
   (elem)->next = list;                         \
   (elem)->prev = (list)->prev;                 \
   (list)->prev->next = elem;                   \
   (list)->prev = elem;                         \
} while(0)

Insert an element to the list tail.

Parameters:

	list	list.
	elem	element to insert.

#define is_empty_list

(

list

)

((list)->next == (list))

Test if a list is empty.

Parameters:

list

list.

Returns:

non-zero if list empty, or zero otherwise.

#define last_elem

(

list

)

((list)->prev)

Get list last element.

Parameters:

list

list.

Returns:

pointer to last element.

#define make_empty_list

(

sentinal

)

Value:

do {                                            \
   (sentinal)->next = sentinal;                 \
   (sentinal)->prev = sentinal;                 \
} while (0)

Make a empty list empty.

Parameters:

sentinal

list (sentinal element).

#define move_to_head	(	list,
		elem		)

Value:

do {                                            \
   remove_from_list(elem);                      \
   insert_at_head(list, elem);                  \
} while (0)

Move an element to the list head.

Parameters:

	list	list.
	elem	element to move.

#define move_to_tail	(	list,
		elem		)

Value:

do {                                            \
   remove_from_list(elem);                      \
   insert_at_tail(list, elem);                  \
} while (0)

Move an element to the list tail.

Parameters:

	list	list.
	elem	element to move.

#define next_elem

(

elem

)

((elem)->next)

Get next element.

Parameters:

elem

element.

Returns:

pointer to next element.

#define prev_elem

(

elem

)

((elem)->prev)

Get previous element.

Parameters:

elem

element.

Returns:

pointer to previous element.

#define remove_from_list

(

elem

)

Value:

do {                                            \
   (elem)->next->prev = (elem)->prev;           \
   (elem)->prev->next = (elem)->next;           \
} while (0)

Remove an element from list.

Parameters:

elem

element to remove.

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